W.B. Davis 1935. 4/6 Arco, Butte Co., Idaho, June 73. At Bonanza Bar I made two sets for pocket gophers in the cultivated area and also two sets for Muskrat in a small creek which forms a sort of slough emptying into Snake River. The next morning I had two gophers and two muskrats; one of the latter was a young one and it was discarded. The morning of the 19th I put up specimens until almost 10 A.M. and then I collected by four traps and specimens and drove via American Falls to a ranch about 5 miles by road north west of American Falls on the east side of the river. I hunted on the way and on the east and south side of the river I saw many and collected four C. armatus. They are invariably found near water and prove the worst pests the farmer has to contend with when they are numerous. I arrived at the above ranch about 12:30 and inquired about squirrels and pocket gophers.